Agree as Rick said
Pull the motor and remove pistons and rods from cylinders
Remove main bearing caps
Remove crankshaft
Take crankshaft to machine shop to determine if crank needs to be polished or turned
Machine shop will do work and advise and/or order bearings to match
Pickup plastic gauge
Make sure everything is clean and dry
Install new main bearing halves in block
Lay crank on new bearings (DO NOT TURN CRANK)
Take a piece of plastic gauge and place on top of each main bearing crank journal
Place other half of main bearing in top main bearing cap
Place bearing cap over crank shaft journals and torque to spec.
Remove main bearing caps and measure plastic gauge for oil clearance
If oil clearance is good, remove crank and use engine assembly lube on bearing and crank shaft surfaces and reinstall
